The use of light-emitting diode (LED) strings instead of fluorescent bulbs for use in illumination of a backlight for a display, such as a television or a monitor for a laptop computer is increasing drastically based on consumer demands for better picture quality. In addition, typical LED light efficacy can be much better than conventional lighting systems for such displays, thus consuming significantly less power. In addition, among other advantages, LED systems can be smaller and more environmentally friendly, and can have a faster response with less electro-magnetic interference (EMI) emissions.
A number of LED regulation techniques exist for typical LED systems, such as constant-current regulation, constant-voltage regulation, and a combination of constant-current/constant-voltage regulation. The typical LED regulation schemes each have separate advantages and disadvantages. For example, some of the LED regulation schemes sacrifice cost for design simplicity. Other schemes are less expensive, but have a much slower dimming frequency. Yet other schemes have sufficient dimming capability but are less efficient with respect to power consumption and may also have more complicated circuit designs and implementations.